Microcomputers have been utilized in microwave oven controls for many years. Generally, the microcomputer stores an operational program that operates on control data entered by the operator through a control panel. For example, the operator may enter a future time at which a cooking operation is to be commenced. Also, the operator may enter control data that alters the cooking profile such as data that specifies the power level or sets a temperature probe control. Further, the microcomputer can be programmed by the control data input so as to execute a plurality of cooking cycles in sequence.
U.S. Pat. No. 4,390,768, issued Jan. 28, 1983, describes a microwave oven using a microcomputer or microprocessor to control the operation of a microwave oven having a built-in scale coupled to the microcomputer. The microcomputer so described includes a random access memory or similar volatile storage device in which operator control data is stored until its specified operation is completed or the microcomputer is reset. Also, the microcomputer contains a read-only memory or similar nonvolatile storage device for storing the operational program and computational constants so that the microcomputer does not have to be reprogrammed if AC power is interrupted. The operational program and the computational constants are not alterable so that the operating parameters or characteristics of the oven cannot be altered. For example, if a cooking time period calculation is based on the output power of the particular oven, it is necessary to attempt to match the output power of each oven to a standard power which is assumed in the calculations. Also, the available power levels cannot be altered so as to change the profile of a defrost or cook cycle for a particular food category.